Author Topic: Bass acoustic issues  (Read 21606 times)

Offline rollo

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Re: Bass acoustic issues
« Reply #30 on: December 13, 2014, 06:53:17 AM »
   How about you try a passive high pass inside the amp say cut off at 73HZ. That will relieve the amp and drivers for frequencies not required. A huge difference sonically. Then bring up the sub with its crossover until your measurements are correct.
    You will most likely hear the best result as you measure. The rythmic plate amps have an excellent control panel to fine tune.
    to date the most accurate and real sounding bass was produced by Dannie Richies open baffle subs using rythmic amps and a high pass in the amp.


charles
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Offline jimbones

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Re: Bass acoustic issues
« Reply #31 on: December 13, 2014, 11:27:04 AM »

Yes Charles. I have those RCA HP filters I think they are tuned at 50 or 60 hz. Although I remember with my former amp they added a bit of grunge.  I can always try them again as it costs me nothing. I am VERY interested in building the woofers you mention. I would like to operate them up to 275 hz if possible.


   How about you try a passive high pass inside the amp say cut off at 73HZ. That will relieve the amp and drivers for frequencies not required. A huge difference sonically. Then bring up the sub with its crossover until your measurements are correct.
    You will most likely hear the best result as you measure. The rythmic plate amps have an excellent control panel to fine tune.
    to date the most accurate and real sounding bass was produced by Dannie Richies open baffle subs using rythmic amps and a high pass in the amp.


charles
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Offline jimbones

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Re: Bass acoustic issues
« Reply #32 on: December 13, 2014, 08:31:30 PM »
So here's the good and the bad. The HP filters definitely cleaned up the bass which there was a bit too much. The Bad is that the sound is not as pristine as without them. Now I am going to assume that in these little rya thing-a-ma-jigs do not contain great caps. I could make my own HP filters using really hi quality components. I think I'll e mail Dan Wright for the proper values.
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Offline richidoo

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Re: Bass acoustic issues
« Reply #33 on: December 14, 2014, 07:56:01 AM »
Oooh! Nice! I'm glad it made an improvement. Good call rollo!

You don't need Dan Wright for this. I googled the input impedance is 20kOhms.

Looking at your sweeps I think the starting freq for the high pass filter should be 200Hz, but you'll want to swap caps to find the best value. 

Use this calculator to find the starting cap value:
http://www.diyaudioandvideo.com/Calculator/XOver/
Impedances are 20000 (the input impedance of your amp)
200Hz gives  .04uF for the high pass cap
Ignore the low pass info

Schematic diagram for first order high pass filter:
http://www.t-linespeakers.org/tech/filters/passiveHLxo.html

Your amplifier is R2. Just put the cap in series with the line signal. Maybe you can mod the RYA adapters with these caps, just let the caps hang out, you don't need the adapter covers. If you solder plain wires into the adapter )or cut out the old cap, then you can just clip lead the new caps onto the old leads for easy swap and experiment. You'l want to make it fast to switch freqs when deciding what value.

This cap will make the freq ~175Hz  Link

Buy pairs of .01uF, 022uF and .047uF. That will give you a variety of possibilities to try different frequencies by paralleling them together. Paralleling adds capacitor value. Increasing cap value reduces the freq. If you want to try very low freqs like 50Hz then also buy a pair of .1uF. Buy the lowest % tolerance available, but don't sweat it. Link
They offer 1st class mail for cheaper shipping, as does digikey

These caps sound very good, I use them in all my line level stuff. But if you want to upgrade to VCaps/Duelund/Jupiter/ClarityMR  later you'll know what value works.

Offline jimbones

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Re: Bass acoustic issues
« Reply #34 on: December 14, 2014, 08:02:29 AM »
OK so those are Vishay caps. They say they are film but not much info beyond that. I guess they could be poly etc?

« Last Edit: December 14, 2014, 08:21:14 AM by jimbones »
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Offline richidoo

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Re: Bass acoustic issues
« Reply #35 on: December 14, 2014, 08:07:33 AM »
MKT=polyester
MKP=polypropylene

Offline jimbones

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Re: Bass acoustic issues
« Reply #36 on: December 14, 2014, 08:40:40 AM »
Well, Im not confident I'll be able to take apart the Harrison Labs filters. They may even be potted. I have other options such as taking a spare Interconnect and modding it or opening up the amp and putting it on the input jack. (bad thing about that it is not easily removable like a interconnect).
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Offline richidoo

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Re: Bass acoustic issues
« Reply #37 on: December 14, 2014, 09:04:29 AM »
You want the cap out in the open to swap caps.

Or you can determine the best freq using JRiver. Make a 6dB high pass filter in PEQ module of the DSP section. Adjust freq to taste.

Once you decide on a freq, then calc the cap and make up a nice RCA adapter cable with Switchcraft 3502 and 3503 connectors. They are high copper brass and inexpensive.


Offline rollo

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Re: Bass acoustic issues
« Reply #38 on: December 19, 2014, 08:20:01 AM »
  The Harrisons are designed for car audio. OK but we can do better. Attach a lead from the wire of the RCA input and one from wire going to board. This way you can try different caps. The cap choosen will have a big affect. Do not cheap out as the values are small.


charles
contact me  at rollo14@verizon.net or visit us on Facebook
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Offline jimbones

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Re: Bass acoustic issues
« Reply #39 on: December 19, 2014, 06:00:26 PM »
  The Harrisons are designed for car audio. OK but we can do better. Attach a lead from the wire of the RCA input and one from wire going to board. This way you can try different caps. The cap choosen will have a big affect. Do not cheap out as the values are small.


charles

I agree that because the values are small it won't cost much, I just prefer not to dick around with the inside of my amp since I just bought it. Not that I don't have the confidence I'd like to do something external so I can change it out easily. More to come.....
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